Method for crimping and thermally treating yarn

ABSTRACT

CRIMPED YARN IN THE FORM OF A PLUG, SUCH AS IS PRODUCED BY LONGITUDINALLY COMPRESSING AND BUNCHING THE YARN IN A STUFFER BOX, IS CONVEYED, WHILE IN THE PLUG FORM, THROUGH A TREATING ZONE WITH THE AID OF A FLOW OF GAS. IN THE TREATING ZONE THE PLUG OF CRIMPED YARN MAY BE SUBJECTED TO   HEATING AND/OR COOLING TREATMENT TO IMPROVE THE PROPERTIES OF THE YARN. THE FLOW OF GAS IS INDUCED THROUGH THE TREATING ZONE IN THE DIRECTION OF TRAVEL OF THE PLUG PREFERABLY BY SUCTION AT THE EXIT END OF THE TREATING ZONE.

1971 D. A. E. MATTINGLY 3,616,503

METHOD FOR CRIMPING AND THERMALLY TREATING YARN Filed Jan. 3, 1968 I 2 Sheets-Sheet l g7 7 4422? WM K Nov. 2, 1971 o. A. E. MATTINGLY 3,616,503 METHOD FOR CRIMPING AND THERMALLY TREATING YARN Filed Jan. 5, 1968 I3 Sheets-Sheet z I INVENTOR DEN/s flwsprfbmqepfil rrm yzy BY fill/q flaw ATT RNEYS United States Patent ice 3,616,503 METHOD FOR CRIMPIN G AND THERMALLY TREATING YARN Denis Albert Edward Mattingly, London, England, as-

signor to The Klinger Manufacturing Company Limited, London, England Filed Jan. 3, 1968, Ser. No. 695,369 Claims priority, application 61;7eat Britain, Jan. 6, 1967,

Int. Cl. D02g 1/12 US. Cl. 2872.14 6 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a method and apparatus for treating yarn, especially thermoplastic yarn or yarn having a thermoplastic component.

In known methods and apparatus for crimping yarn, the yarn is longitudinally compressed and formed into a plug while in a heated condition and is set in the plug configuration While confined in, for example, a heat-setting chamber to form a plug of crimped yarn. Thereafter the yarn is usually wound from a leading end of the plug onto a take-up package.

Yarn leaving the setting chamber is in a tightly formed plug configuration and normally at a temperature above ambient temperature. We have found that when tension is applied to the yarn as the yarn is wound onto a take-up package and the yarn is still at a raised temperature this tension can remove some of the crimp from the yarn.

It is an object of the present invention to provide a method and apparatus for treating the yarn while in the configuration of a plug of crimped yarn so as to permit the yarn to relax and cool before tension is applied to it, as, for example in subsequent winding of the yarn into a package,

According to an aspect of the invention there is provided a method of treating yarn comprising moving a plug of crimped yarn into a treating zone, conveying the crimped yarn through the treating zone with aid of a flow of gas and withdrawing the yarn from the treating zone.

According to another aspect of the invention there is provided an apparatus for treating yarn including a hollow treating chamber, means for moving or aiding movement of a plug of crimped yarn through the hollow treating chamber comprising means for creating a flow of gas along at least part of the length of the treating chamber, the crimped yarn being conveyed through the treating chamber with the aid of the flow of gas, and withdrawing means for withdrawing the yarn from an exit end of the treating chamber.

During the time in which the plug moves through the treating zone, the crimped yarn is able to relax and fully develop permanent crimp. The amount of time made available for this purpose will depend on the length of the treating zone and the rate at which the yarn passes through the treating zone.

Preferably the fiow of gas is induced by withdrawing gas from the treating zone by suction means and, if desired, the apparatus may also include blowing means for 3,6165% Patented Nov. 2, 1971 blowing gas into an entry end of the treating chamber to assist the suction means to create said flow of gas. Alternatively, a gas-blowing means can be used for creating the gas flow.

The gas, which may conveniently be air, should be at a lower temperature than that of the plug of crimped yarn entering the treating chamber so as to effect a cooling of the yarn while it is still in the form of a plug and before it leaves the treating chamber. Thus the gas may conveniently be air at ambient temperature.

Control means may be arranged to control the rate of withdrawal of crimped yarn from the exit end of the treating chamber. Such control means may be sensitive to the rate of movement of yarn along the treating chamber or the amount of the plug of crimped yarn accumulated in the treating chamber, and may comprise photoelectric control means.

In one embodiment of the invention, the control means is a photo-electric means and includes two photo-cells spaced along the length of the treating chamber for sensing a build-up of the plug of yarn in the chamber at respective spaced apart positions. The control means in this case may be arranged to speed up and slow down the withdrawing means when the plug of crimped yarn builds up to a predetermined amount in the treating chamber, so that the end of the build-up tends to be maintained intermediate the respective spaced apart positions.

The treating chamber may comprise a hollow tube formed of glass, metal of other suitable material.

A tube of glass or transparent plastic material is particularly suitable in cases where a photo-electric control means is provided and depends for its operation upon light transmitted or reflected through the wall of the tube in order to sense the amount of build-up of the plug in the tube.

Alternatively, the tube may be made of metal in which case a transparent Window or windows are provided in it to permit photo-electric means to sense the amount of build-up of the plug.

The tube may be straight or curved and may be arranged in a generally horizontal or vertical position. Preferably the tube is arranged vertically or at an angle, say about 10 to 40, to the vertical.

The tube may have a constant internal cross-sectional area or may be flared towards the end at which the yarn is withdrawn. The size of the bore of the tube is sufficient to permit the plug of yarn to expand freely in an unconfined manner after leaving the setting chamber in which it has been previously confined, and preferably is suflicient to permit the plug to pile up in loosely folded condition.

Certain advantages have been found in providing straight hollow tubes, primarily in respect of maintaining frictional forces exerted on the yarn at a minimum value. If it is required to have treating chambers of, say 4 ft. to 6 ft. long or more, then for practical reasons (that is, so that the dimensions of the overall crimping apparatus does not become too large) it may be necessary to make the chamber of, for example, U-shape or J-shape.

An apertured connector may be provided at or adjacent the yarn-exit end of the treating chamber to allow gas to escape from the chamber, to for example, the suction means. The connector may have a plurality of apertures so arranged that crimped yarn is not drawn through the apertures towards the suction machine.

Where the plug of crimped yarn is formed in a crimping apparatus which includes a heat setting chamber and yarn engaging means (for example, a toothed wheel) for moving the yarn through the heat setting chamber, there may be provided a hollow shoe which is arranged to dis- 3 engage the yarn from the yarn engaging means and guide the yarn into the treating chamber. This shoe may be pro vided with gas ports to allow gas to enter the yarn entry end of the treating chamber for assisting the advance of the plug into and/or through the treating chamber.

Heavy denier yarns (say 2,0004,000 denier), especially polypropylene yarns, have comparatively high heat retentivity, and may remain at an elevated temperature for comparatively long periods of time after they leave the heat setting chamber. The invention makes it possible to provide a comparatively long time interval (say 45 seconds and even longer) between the instant the plug of crimped yarn leaves the heat setting chamber of a crimping apparatus and the instant the crimped yarn is subjected to tension by being wound onto a take-up package, thus allowing the crimped yarn to cool and relax before being subjected to tension. When crimping polypropylene yarn, we have found that the treating chamber is required to be longer than for treating, say nylon yarn of the same denier.

A stuffer box crimping apparatus having a treating chamber according to the invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 shows one form of the apparatus diagrammatically; and

FIG. 2 is a fragmentary view illustrating a modification of the apparatus of FIG. 1.

Referring to the drawing, flat, i.e. uncrimped, yarn, such as for example nylon. polyester or polypropylene is fed from a supply bobbin 1 around a feed roller 2 and an idler roller 3 and in contact with the heating surface of a heater 4. The yarn leaving the heater is fed by a pair of driven nip rollers 5 into a stuffer box crimping chamber 6 of short length and the heated yarn is com pressed longitudinally in the chamber to form a plug of crimped yarn. This plug, which is illustrated schematically is removed from the outlet of the crimping chamber 6 by the periphery of a driven toothed conveyor wheel 7 which is arranged to move the plug of crimped yarn through an arcuate setting chamber 8 which may be heated by any suitable means.

The rate at which the toothed conveyor wheel conveys the plug of crimped yarn through the setting chamber is regulated so that the yarn becomes heat set in the crimped configuration.

A tubular shoe 11 is positioned at the outlet end of the setting chamber and arranged to guide the plug of crimped yarn in to a treating chamber.

The treating chamber comprises a smooth bored glass tube 10, mounted on a bracket 12, with its entry end positioned to receive the plug of crimped yarn from the shoe 11. At the exit end of the tube is attached an air suction connector 13 (shown in section) which includes a multi-aperture cylindrical part 14 and a nozzle 15 for connection to a suction pipe. The connector 13 has a hingedly mounted bottom wall formed with an aperture 16 through which crimped yarn can be withdrawn. The aperture 16 is large enough for the yarn to pass through when unravelled from the plug but is not large enough for the plug itself to pass through. The bracket 12 is supported by a pivot 17 and a screw 18 through a slot 19 in the bracket. A projection 20 on the bracket 12 is positioned adjacent a micro-switch 21. The micro-switch is supported by a framework (not shown) of the crimping apparatus.

A sensing device 24 comprises two photo-electric cells 22 and 23 and a light source for each cell arranged to direct light into the corresponding cell.

The photo-electric cells 22 and 23 and light sources are located outside the tube 10 and spaced apart along the tube. The cells are arranged to sense light emitted from their corresponding light sources which light passes through the tube. The cells provide control signals in response to changes in the intensity of the light they receive.

The yarn is withdrawn through the aperture 16 by winding means which comprises a takeup bobbin 27, a traversing guide 28, and a drive roller 25 for the takeup bobbin. A variable speed electric motor 26, which is connected to the electrical supply terminals 26A, drives the driven roller 25. The yarn leaving the aperture 16 passes round a guide roller 29 and through tensioning rollers 30 and is wound into a package on the bobbin.

A controller 31 connected to the photo-cells 22 and 23 is arranged to control the speed of the motor 26 in response to control signals from the photo-cells.

In operation, the plug of crimped yarn enters the tube 10 through the shoe 11 from the setting chamber 8. An air suction means (not shown) connected to the nozzle 15 by an air pipe draws air out of the tube at its exit end so causing an air fiow into the yarn entr end of the tube and through the tube. This air flow aids movement of the crimped yarn through the tube towards the aperture 16.

The plug of crimped yarn is advanced from the setting chamber by the toothed wheel and enters the horizontal part of the tube 10 where it is engaged by the air flow. In the tube, the plug of crimped yarn falls under gravity down the tube towards the exit end of the tube and is assisted by the air flow.

The rate of withdrawal of the yarn through the aperture is controlled by the controller 31 which controls the speed of the winding means. When an accumulation of the plug of crimped yarn builds up in the tube from the exit end of the tube, this built-up accumulation interrupts the light passing through the tube from the light source to the photo-cell 22. This causes the intensity of light received by this photo-cell to fall below a predetermined intensity. As a result, the controller 31 responds to the different output from the photocell 22 and causes the speed of the winding means to increase so that the rate of withdrawal of crimped yarn through the aperture 16 is increased. Thereafter and in consequence, the build-up of crimped yarn in the tube tends to fall below the position of the photo-cell 22 so that the intensity of the light reaching the photo-cell 22 will increase to said predetermined intensity a ain.

When the end of the build-up of the plug of crimped yarn is so reduced that the photo-cell 23 also senses light of the predetermine intensity, the controller in response to an appropriate control signal from the photo-cell 23 is arranged to cause the speed of the winding means to reduce so that the build-up of yarn tends thereafter to increase.

The control mechanism is arranged to tend to maintain the trailing end of the build-up intermediate the two photo-cells 2,2 and 23 by controlling the rate of withdrawal of the crimped yarn through the aperture 16.

The crimping apparatus includes a safety device arranged to cause the crimping apparatus to be switched off in case of faulty operation of the crimping apparatus which results in the plug of crimped yarn filling the tube 10. Once the entry end of the tube is filled or packed with the accumulated plug of yarn, additional plug advancing from the setting chamber 13 into the shoe 11 will create a high pressure at the entry of the tube 10. When this pressure rises to a predetermined value, the bracket 12 and the tube 10 will be caused to move relative to their mounting away from the shoe 11 by the increased pressure. That is, the bracket will swing about the pivot 17, the slot 19 allowing the bracket to move with respect to the screw 18. The pressure value of the predetermined pressure at which the bracket is caused to move away is dependent on the tightness of the screw 18 on the bracket 12 and can be adjusted. As the bracket swings about the pivot 17, the projection 20 presses onto and operates the microswitch 21 which cause the crimping apparatus to be switched off.

The suction connector 13 defines a walled chamber in which the apertured cylindrical part 14 is disposed in continuation of the tube and from which air or other gas can be drawn through the nozzle 15, so as to induce a flow of gas or air through the tube 10 and outwardly through the aperture cylindrical part 14 while the yarn plug moves substantially axially through the cylindrical part 14 to the bottom wall at which yarn is withdrawn from the head of the plug. A slot is provided in the hinged bottom wall of the connector 13 extending from the edge of the wall to the aperture to allow yarn to be slid into the aperture 16 to facilitate threading up of the apparatus.

The suction connector 13 may be arranged with an aperture in its side, rather than its end as described. In this arrangement the end of the suction adapter is perforated to provide an exit path for the air flow.

It will be appreciated that the length of the tube may be varied for applications in which the yarn being crimped requires greater or lesser cooling time.

The cross-sectional area of the treating chamber is arranged to be greater than the cross-sectional area of the setting chamber to allow the plug of crimped yarn entering the treating chamber to increase its cross-sectional area and to relax.

In the described embodiment, the appropriate internal diameter of the glass tube is dependent on the amount of crimp applied to the yarn, the denier and the composition of the yarn. The diameter is arranged to be large enough to allow the yarn to relax and not so large as to readily permit the yarn to become entangled in the tube. Entanglement is less likely to occur if crimps along the length of the yarn are held in proper sequence. If the diameter of the tube is too large, later crimped parts along the length of the yarn may move ahead of earlier crimped parts in the glass tube. If this happens the yarn will tend to become jammed at the exit of the tube so that withdrawal of yarn therefrom is hindered or prevented.

The following example illustrates the use of the invention:

1,100 denier, 70 filament nylon yarn was crimped using a glass tube 2 ft. 6 inches long, having an inch diameter bore and shaped as shown in the drawing. Photo-cells were positioned approximately 10 ins. and ins. from the exit end of the tube. The yarn throughout speed between the rollers 5 was 1,400 ft./min. and the diameter of the setting chamber was /8 inch. Air at ambient temperature was drawn through the tube by a suction machine connected to the suction connector at the exit end of the glass tube.

In a modification of the described embodiment, illustrated in FIG. 2, in which parts similar to those of FIG. 1 are indicated by similar reference numerals having a dash, the crimped yarn is heated in a physically relaxed condition after being crimped and before being tensioned and wound onto the take-up package. In such a modification the air (or gas) flowing through at least part of the glass tube, adjacent the entry end of the tube, is heated rather than cooled or at ambient temperature. The shoe 11 is provided with an adaptor for receiving a supply of heated air or gas and admitting the air or gas into the inlet end of the tube 10. The tube 10' has a perforated portion 42 at a position intermediate between its ends. A manifold 44 surrounds the perforated portion 42 of the tube, and is divided into upper and lower chambers 46 and 48, respectively. The upper chamber 46 forms a suction adaptor through which heated air admitted to the tube through the adaptor 40 is withdrawn after passing through the upper part of the tube. The lower chamber 48 of the manifold forms an inlet for cooling air which, after passing downwardly through the lower part of the tube is withdrawn through the air suction connector 13 at the exit end of the tube.

The photoelectric sensing device 24' is positioned in the upper part of the tube above the manifold 44. This arrangement permits a flow of heated air between the entry end of the tube and a position intermediate between the ends of the tube, and another flow of air, cooled or at ambient temperature, between the intermediate position and the exit end of the tube. Thus the first part of the glass tube may constitute a heat setting zone, or part of a heat setting zone, in which heat is applied to crimped yarn in a physically relaxed condition, and a second part of the glass tube may constitute a cooling and relaxing zone. In addition or alternatively, the tube 10 or part of the tube is heated by, for example, electrical means whereby the crimp characteristics of the yarn are modified.

It will be appreciated that yarn treating agents, such as moisturing and finishing agents, may be applied to the yarn in the treating chamber to improve or modify the properties of the crimped yarn produced by the crimping apparatus.

A I claim:

1. A method of continuously treating yarn comprising feeding yarn in a heated condition into a crimping zone, compressing the yarn longitudinally in the crimping zone to form a plug of crimped yarn, conveying the crimped yarn through a setting zone, transferring the crimped yarn to a treating zone, conveying the crimped yarn through the treating zone with the aid of a fiow of gas and allowing the crimped yarn to cool in an unconfined condition in the treating zone, the crimped yarn being maintained in plug configuration throughout the aforementioned steps, and then withdrawing the yarn from the leading end of the plug of crimped yarn.

2. A method of continuously treating yarn comprising feeding yarn in a heated condition into a crimping zone, compressing the yarn longitudinally in the crimping zone to form a plug of crimped yarn, heat setting the yarn while confining it in its plug-like configuration, advancing the crimped yarn to a treating zone, inducing a flow of gas through the treating zone in the direction of advance of the yarn, cooling the yarn in an unconfined condition in the treating zone, the crimped yarn being maintained in plug configuration throughout the aforementioned steps, and then withdrawing yarn from the leading end of the plug of crimped yarn.

3. A method according to claim 2 including sensing the progress of the plug of crimped yarn through the treating zone and controlling the rate of withdrawing yarn from the leading end in response to said progress.

4. A method according to claim 2 in which the gas flow is induced by sucking the gas through the treating zone.

5. A method of treating yarn according to claim 2 in which the plug of crimped yarn is positively engaged at an exit end of the crimping zone and positively transported from the crimping zone into a zone for the heat setting.

6. A method according to claim 2 in which the yarn is conveyed through the treating zone without being subjected to tension therein.

References ited UNlTED STATES PATENTS 2,924,001 2/1960 Gundlach 281.6 2,983,026 5/1961 Skalko 19-66 A X 3,174,206 3/ 1965 Mattingly et al. 28l.7 3,241,212 3/1966 Evans et al. 28l.5 3,292,231 12/ 1966 Epstein 28--1.6 3,390,438 7/1968 Epstein 28-l.6 3,397,437 8/1968 McNeill et al. 28-21 ROBERT R. MACKEY, Primary Examiner U.S. Cl. X.R. 281.7 

